From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9530C282C0 for ; Fri, 25 Jan 2019 07:59:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 98A4A20820 for ; Fri, 25 Jan 2019 07:59:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548403159; bh=enNDhpmKlJ5lN57BnZgyA8ttjZBGNhzfOKtP5fzWL4Q=; h=Subject:To:From:Date:List-ID:From; b=YzTK9NGqjATM48oRO1bSSPLrM8K/VDmnd9xSNXKqy8+yVXII9ShDplTAGChhrKJyj 3XsdDDTgNFQbdireXtW4J0vmnemgn4S9Pot774IptgV+xbuOujNVdJxotzqd0tDyfa Z3qYnZDzrIfLMTPfl6+fkDfessZfM0dLYWl26AmM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729145AbfAYH7R (ORCPT ); Fri, 25 Jan 2019 02:59:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:38662 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726271AbfAYH7Q (ORCPT ); Fri, 25 Jan 2019 02:59:16 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3AE6720820; Fri, 25 Jan 2019 07:59:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548403155; bh=enNDhpmKlJ5lN57BnZgyA8ttjZBGNhzfOKtP5fzWL4Q=; h=Subject:To:From:Date:From; b=ZkSuRqytiCF9UjrOXMnn7WXkbQXJi///sCPuUcZepC2u5U4Ltl9k8Sn9R78HKXrD8 rK1WBP3cM0DlTVTb6WaFs2770S27iTuGR7EH+vecXhb1swKylygujU7sABSGVRMzyH KAy07pREkJ50SNHCdKB5qZrtIGZOT3mj47Mj9RAA= Subject: patch "ihex: Simplify next record offset calculation" added to driver-core-next To: andrew.smirnov@gmail.com, akpm@linux-foundation.org, cphealy@gmail.com, dwmw2@infradead.org, gregkh@linuxfoundation.org, kyle@kernel.org, linux-kernel@vger.kernel.org, yamada.masahiro@socionext.com From: Date: Fri, 25 Jan 2019 08:58:42 +0100 Message-ID: <154840312282243@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a note to let you know that I've just added the patch titled ihex: Simplify next record offset calculation to my driver-core git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git in the driver-core-next branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will also be merged in the next major kernel release during the merge window. If you have any questions about this process, please let me know. >From 9fb4ab4d3dd665a62da9c176a89e7c7feaf5d9e4 Mon Sep 17 00:00:00 2001 From: Andrey Smirnov Date: Thu, 20 Dec 2018 23:28:39 -0800 Subject: ihex: Simplify next record offset calculation Next record calucaltion can be reduced to a much more tivial ALIGN operation as follows: 1. Splitting 5 into 2 + 3 we get next = ((be16_to_cpu(rec->len) + 2 + 3) & ~3) - 2 (1) 2. Using ALIGN macro we reduce (1) to: ALIGN(be16_to_cpu(rec->len) + 2, 4) - 2 (2) 3. Subsituting 'next' in original next record calucation we get: (void *)&rec->data[ALIGN(be16_to_cpu(rec->len) + 2, 4) - 2] (3) 4. Converting array index to pointer arithmetic we convert (3) into: (void *)rec + sizeof(*rec) + ALIGN(be16_to_cpu(rec->len) + 2, 4) - 2 (4) 5. Subsituting sizeof(*rec) with its value, 6, and substracting 2, in (4) we get: (void *)rec + ALIGN(be16_to_cpu(rec->len) + 2, 4) + 4 (5) 6. Since ALIGN(X, 4) + 4 == ALIGN(X + 4, 4), (5) can be converted to: (void *)rec + ALIGN(be16_to_cpu(rec->len) + 6, 4) (6) 5. Subsituting 6 in (6) to sizeof(*rec) we get: (void *)rec + ALIGN(be16_to_cpu(rec->len) + sizeof(*rec), 4) (7) Using expression (7) should make it more clear that next record is located by adding full size of the current record (payload + auxiliary data) aligned to 4 bytes, to the location of the current one. No functional change intended. Cc: Chris Healy Cc: Kyle McMartin Cc: Andrew Morton Cc: Masahiro Yamada Cc: David Woodhouse Cc: Greg Kroah-Hartman Cc: linux-kernel Signed-off-by: Andrey Smirnov Signed-off-by: Greg Kroah-Hartman --- include/linux/ihex.h | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/include/linux/ihex.h b/include/linux/ihex.h index 9130f307a420..98cb5ce0b0a0 100644 --- a/include/linux/ihex.h +++ b/include/linux/ihex.h @@ -21,14 +21,18 @@ struct ihex_binrec { uint8_t data[0]; } __attribute__((packed)); +static inline uint16_t ihex_binrec_size(const struct ihex_binrec *p) +{ + return be16_to_cpu(p->len) + sizeof(*p); +} + /* Find the next record, taking into account the 4-byte alignment */ static inline const struct ihex_binrec * __ihex_next_binrec(const struct ihex_binrec *rec) { - int next = ((be16_to_cpu(rec->len) + 5) & ~3) - 2; - rec = (void *)&rec->data[next]; + const void *p = rec; - return rec; + return p + ALIGN(ihex_binrec_size(rec), 4); } static inline const struct ihex_binrec * -- 2.20.1